The use of separate and adjustable feet adjacent to the bottoms of furniture and equipment legs is well known in the art. These feet provide a means for adjusting the height of each leg, allowing the legs to be leveled to insure the stable positioning of the furniture or equipment regardless of the unevenness of the floor on which it is placed.
A typical adjustable foot includes an insert portion that is inserted and retained within the furniture or equipment leg, and a threaded foot portion that threads into a hole within the insert portion to allow the foot to be adjusted upward and downward. These threaded portions have traditionally been manufactured of materials, such as zinc, into which threads are commonly machined. As these materials do not have an aesthetically appealing finish, it is often necessary to include sleeves and caps of a different material over the insert and foot portions to provide an appealing finish. In addition, the thickness of the threaded insert sections, coupled with the materials used, necessitates the use of a separate retaining ring to prevent these inserts from withdrawing from the furniture or equipment leg.
Although prior art leg inserts perform their desired function in a satisfactory manner, the number of parts of differing materials that are utilized, the machining steps involved in preparing those parts, and the assembly required to provide a finished insert, increase the cost of these leg inserts to a point where they are not cost effective for lower priced furniture or equipment. Thus, there is a need for an adjustable leg insert that minimizes the number of parts, eliminates the need for parts of differing materials, does not require extensive machining steps and is relatively simple to assemble, thus providing a simplified, yet functional and aesthetic, replacement for what now exists.
A number of United States Patents have issued relating to adjustable feet. However, none of these patents meets the above referenced need. For example, U.S. Pat. No. 2,384,020, titled "ADJUSTABLE LEG", discloses a leg that includes a leg insert that is adjusted through adjustment of a wedge portion within the leg. This adjustable leg is limited to substantially straight legs, has a limited range of adjustment and includes a number of component parts that must be assembled.
U.S. Pat. No. 2,750,709, titled "REVERSIBLE LIFT FOR FURNITURE LEGS", discloses an attachment to a straight furniture leg that frictionally locks the leg at a desired height. These lifts must also be used with substantially straight legs, and include a number of component parts of differing materials that must be machined to exacting tolerances and assembled.
U.S. Pat. No. 3,191,212, titled "ADJUSTABLE FLOOR GLIDE", discloses a threaded floor glide that mates with a plastic retainer within a furniture leg. Though requiring fewer parts, this glide still requires the use and assembly of machined parts, and parts of different materials. Further, the extension of the threaded portion beyond the level of the leg bottom exposes the threads, detracting from the aesthetic appeal of the chair.
U.S. Pat. No. 3,641,620, titled "FURNITURE GLIDE", discloses a glide assembly attached to a hollow lower portion of a furniture leg that includes a screw stud having a cylindrical plug projecting from the bottom of the leg upon which is supported a free moving vertically displaceable sleeve having a skirt slidable between the periphery of the plug and the walls of the leg. This glide, typical of many prior art designs, includes a multitude of machined parts and requires a substantial degree of assembly.
U.S. Pat. No. 3,720,978, titled "INDEXING FURNITURE GLIDE", discloses a glide that may be adjusted axially through the use of indexing leaf springs that are set on edge and resiliently biased against flats on a foot-ended stud that is threaded up to a nut fixed in the leg, so as to yieldably stop the stud at quarter turn intervals when the foot is rotated to thread the stud further up into or down from the nut. As described, this glide requires that a multitude of component parts be machined and assembled.
U.S. Pat. No. 5,536,068, titled "CHAIR WITH ADJUSTABLE LEGS", discloses an adjustment mechanism that includes an internally threaded insert sleeve received within a hollow area of the leg member and a leg extension having an external thread that is dimensioned to mate with the internal thread of the leg extension. This mechanism includes fewer component parts than other designs and, thus, is easier to assemble. However, the insert sleeve and threaded leg extension must both be machined to mate with each other and, as with other designs, the threads of the leg extension are exposed, detracting from the aesthetics of the chair.
Finally, U.S. Pat. No. 5,588,624, titled "TABLE LEG EXTENSION", discloses an extension for supporting a leg of a table that includes a receiving tube within which the leg is disposed, an abutment plate mounted within the tube for engaging and supporting the leg in a spaced relationship relative to the lower end of the tube, and a threaded member attached to the abutment plate. As with the other designs cited, this design requires a multitude of machined parts that must be assembled and results in an extension having exposed threads that detract from the aesthetics of the furniture to which it is mounted.
In the prior art, there is not found an adjustable leg insert that does not require a large number of parts, that eliminates the need for parts of differing materials, that does not require extensive machining steps, that is relatively simple to assemble, and that does not include exposed threads that detract from the aesthetics of the furniture or equipment to which it is mounted.